杭州某国道明挖下穿对既有市政高架桥桥墩影响分析

Analysis of the influence of open-cut undercrossing of a national highway in Hangzhou on the existing municipal viaduct piers

为研究235国道明挖下穿对留祥路西延互通主线桥桥墩的影响,本文结合现场监测和有限元模拟对其展开了分析。基于依托工程,采用Plaxis 3D数值分析软件建立了地层与结构的三维计算模型,其中土体采用HSS本构模型模拟,对下穿段明挖隧道施工的全过程进行仿真模拟,分析了235国道隧道段明挖下穿施工对两侧桥墩的变形和受力的影响。隧道段基坑开挖施工过程中,围护结构水平位移的有限元计算结果与实测结果吻合较好,验证了计算模型的有效性,并说明了HSS本构模型能较好地模拟下穿段的明挖施工。有限元计算结果表明,在235国道隧道段的明挖施工、隧道建造等整个建造过程中,两侧高架桥桥墩均受到一定影响,主线桥桥墩的最大水平位移、竖向位移均满足变形控制要求,结构处于安全状态。

To investigate the influence of open-cut undercrossing of national highway 235 on the main bridge piers of Liuxiang Road west extension interchange,this work employed a combination of field monitoring and finite element simulation.Based on the supporting project,the three-dimensional computational model for both stratum and structure established using Plaxis 3D numerical analysis software,incorporated the HSS constitutive model to simulate the soil behavior.The entire process of open-cut tunnel construction in the undercrossing section was simulated.This analysis delved into the influence of the open-cut tunnel section of national highway 235 on the deformation and stress of piers on both sides of the main bridge of Liuxiang Road west extension interchange.Throughout the excavation of the foundation pit in the tunnel section,the finite calculation results for the horizontal displacement of the bracing structure closely aligned with the measured results,validating the calculation model.This affirmed the efficacy of the HSS constitutive model in simulating the open-cut construction of the undercrossing section.Finite element calculations revealed that,over the entire construction process of the open-cut construction and tunnel construction of the national highway 235 tunnel section,the viaduct piers on both sides experienced a certain degree of impact.The maximum horizontal and vertical displacements of the main bridge pier conformed to the deformation control requirements,ensuring the structural integrity and safety.